In this sentence we would be looking into am alternate for the word "Charisma" from the options given below,
Charisma means compelling attractiveness or charm that can inspire devotion in others. Charm means the power or quality of delighting, attracting, or fascinating others.
Charm is the correct alternative
If we look into the other options,
humility means the quality of having a modest or low view of one's importance.
Power means the ability or capacity to do something or act in a particular way.
Candour means the quality of being open and honest; frankness.
Option C is correct